Mankind has, for at least since the beginning of recorded history, been raising and storing hay and other animal feeds for wintertime use. Throughout the ages this has been accomplished without the aid of farm machinery. With the introduction, around the turn of the century, of power-driven farm machinery, significant changes in the method in which hay is stored have been made.
An early development in agricultural engineering was the automatic hay baler. While there have been numerous and important design changes throughout the years that automatic hay balers have been used, the basic principles have remaned the same. The field of hay to be baled is first cut by a machine commonly known as a swather and collected in rows, called windrows, behind the swather. The hay is left in the windrows, exposed to the sun and wind and left to dry.
The hay baler, usually towed behind a tractor, is then guided down the windrows of hay, where it scoops up the hay in the windrow, conveys it into the baler where a piston, press or similar apparatus packs it into a chamber. As the piston works, an attached cutting edge shears the hay to form one side of the bale. When the bale reaches a predetermined size, the hay baler automatically wraps the bale with twine or wire and the wrapped bale is transferred to the rear of the hay baler where it is dropped onto the field for later retrieval.
By the very nature of the hay baling process the hay bale is created which has four distinct sides. Two of the sides of the bale, called the string sides, are the sides which are wrapped with the twine, and are similar with the strands of hay laying in a relatively uniform parallel pattern at a 90.degree. angle to the strands of wire which hold the bale together. Another of the sides is called the cut side and is that side which was sheared by the cutter in the automatic hay baler. The fourth side is the chamber side and is that which was up against the rear wall packing chamber of the automatic hay baler. In practice it has been found that there is a distinct difference between the cut side and the chamber side of the hay bale. The cut side has a much more uniform configuration of blades and strands of hay. The chamber side of the bale has blades and strands of hay compressed together in numerous and various directions, is not nearly as regular as the sheared end, and can withstand more compression without distortion.
Prior to the development of automatic retrieval systems for hay bales, the common practice, which is still widely used today, was for laborers to manually pick up the bales from the field and toss them onto a wagon where a second laborer would stack the hay. Once the hay wagon was fully stacked, it would be towed to the storage facility or a location where the laborers would manually unload the bales, stacking them for storage. In practice it was best to pick up the bales by the baling wires and to stack them cut side up since this placed the chamber side down. The chamber side being more randomly packed, provided a firmer base for the bale, hence allowed stacking more bales higher.
As long as the hay bales were retrieved manually, it was of little importance which way the bale was deposited on the ground by the automatic bale maker. In fact, most bales were deposited string side up, which was the most convenient position for the laborers to retrieve the bale from.
A second feature common to nearly all hay balers is that they are designed to be positioned behind the tractor in such a manner that the windrow hay pick-up portion of the baler is displaced to the right of the tractor. The reason for this is that it allows the farmer, when he reaches the end of a windrow, to turn to his right to travel up another windrow without driving his tractor across the windrow. As a result, farmers have traditionally used a method of baling hay which requires the farmer to alternate the windows as he moves up and down the field. The direction of travel is similar to a looping action where the farmer enters the field at the head of the windrows, skips the first windrow and moves his hay baler down the second windrow, turning to his right at the end and travels up the first windrow, turns to his right again skipping the third windrow, moving down to the fourth windrow then turning right again traveling up the third windrow, then turning right at the head of the field and skipping the fifth windrow and moving down the sixth one, and so forth. If the farmer did not use this alternating, looping method of travel, he would be required to turn right at the head of the field and left at the bottom.
A third feature common to nearly all hay balers, and this is created by the basic design of hay baler, is that the bale of hay exits the hay baler at a position laterally displaced from the windrow. In practice the hay balers currently in use displace the hay bale approximately three to four feet to the left of the windrow.
As a result of the combination of the lateral displacement of the bale to the left and the farmer's looping action to the right, is that a double row of bales is created.
When hay was manually removed from the field, there was a significant advantage to this double row since all of the bales were string side up, and there were two rows of bales closely spaced together.
Additionally, as long as the farmer's tractor was not too large, there would be room for the tractor to make the upfield windrow run between the bales of hay on his left and the windrow on his right.
This doublerow of string side up bales did not pose many significant problems during the early stages of development of automatic bale retriever systems. The first bale retrievers were merely motorized ramps which lifted the bale off the field and conveyed it up to a platform where it was still manually stacked by the laborer. For this type of operation it was still advantageous to leave the bales in the field string side up, since the transverse strands of hay were easily caught by a cog in a chain pick-up device and when the bale reached the end of the motorized ramp the strings were easily accessible to the laborer for picking up the bale and stacking it.
With the development of automatic retrieval and bale stacking devices, the position of the bale in the field has become significantly more important. There are numerous reasons for this, the first and foremost of which is that it is most desirable to stack the bales cut side up. If a bale lays in the field string side up, the automatic retriever and stacker must reposition the bale prior to stacking it.
A second reason is that there is a distinct difference in the strength with which the bale wires hold the bale together between the cut side and the chamber side of the bale. The string closest to the chamber side compresses the hay uniformly since that is the area of the bale where the blades of hay are most randomly mixed. The cut side string, while having the same compression as the chamber side string, is holding that portion of the bale which is far more uniformly layered. Additionally, the cut side has a tendency to have the strands of hay uniformly canted off in one direction near the cut side edge of the bale, which is caused by the action of the automatic bale cutter. For that reason the string on the cut side of the bale has a tendency to be more easily pulled off of the bale.
This presents significant problems to automatic retrieval and stacking systems. If the bale is lying cut side down the retrieval system must operate at a slower rate of speed so as to not pull or distort the bale to the point where the cut side string will pull off. To prevent this, the automatic retrieval systems are operated at a lower rate, hence, slowing down the entire operation of retrieval and stacking.
The most advantageous way of method to retrieve the bales is to have them all positioned uniformly cut side up so that the retriever can operate at maximum efficiency and the stacker does not have to manipulate or turn the bale prior to placing it in the stack.